This invention relates to the preparation of alkoxylated tertiary amines and, more particularly, to an improved process for the preparation of alkoxylated tertiary amines from an oxyalkylated alcohol and a secondary amine using, as an amination catalyst, a catalyst obtained by combining Raney nickel and molybdenum. The alkoxylated tertiary amines made by the process of the invention are useful as biocides, corrosion inhibitors and fuel additives.
It is known in the art to manufacture alkoxylated tertiary amine compounds by reacting an oxyalkylated alcohol with a secondary amine in the presence of a reductive amination catalyst.
Kesling et al., European Patent Application No. 0 180 455 discloses a process for selectively preparing alkoxylated tertiary amine compounds having the general formula: ##STR1## by reacting an oxyalkylated alcohol of the formula: ##STR2## or a mixture of such alcohols, with a secondary amine of the formula HNR.sub.3 R.sub.4 at a temperature in the range of from about 150.degree. C. to 325.degree. C. and a pressure of from about 50 psig to 3000 psig in the presence of from 0.5 to 20 wt % of an amination catalyst based on the total reaction mixture and wherein R is a straight or branched chain alkyl group having from 1 to 11 carbon atoms, a cyclic alkyl group having from 5 to 10 carbon atoms, an aryl group having up to 12 carbon atoms, or an aralkyl or alkaryl group having up to 18 carbon atoms, R.sub.1 is a single unit or a series of units of the formula: ##STR3## wherein in each unit R.sub.5 is independently selected from the group consisting of hydrogen and a straight or branched chain alkyl group having from 1 to 12 carbon atoms and x is an integer of from 0 to 40, R.sub.2 is hydrogen or a straight or branched chain alkyl group having from 1 to 12 carbon atoms, R.sub.3 and R.sub.4 are each independently selected from the group consisting of straight and branched chain alkyl groups having from 1 to 12 carbon atoms, cyclic alkyl groups having from 5 to 10 carbon atoms, 1 to 4 carbon atom alkyl substituted or unsubstituted benzyl groups and allyl.
Amination catalysts described as being useful in the proess include Raney nickel, supported noble metals, and catalysts containing Cu, Cr and promoters such as nickel. Catalysts containing CuO and Cr.sub.2 O.sub.3 in various ratios, Cu-Cr supported on magnesium aluminate spinel and ruthenium on activated carbon are reported to be preferred catalysts. A selectivity to the alkoxylated tertiary amine product of 98% using, as an amination catalyst, 5 wt % copper chromite supported on magnesium aluminate spinel is disclosed in Example 31.
One disadvantage of this process is that it is carried out at elevated pressures of from about 50 psig to 3000 psig, preferably from about 100 psig to 250 psig which necessitates the use of pressure equipment. Accordingly, it would be advantageous if the process could be conducted at ambient pressure so that the use of such equipment could be avoided.